Noise Elimination Method in Automatic Fire Detection Equipment in Accordance with the Communication Distance

This research focused on the communication noise level depending on the distance for conventional fire detection systems (RS-485 codetransmitter) in comparison to the newly developed optical cable automatic fire detection system (optical communication code-transmitter. The noise levels of the RS-485 code-transmitter were respectively 10, 200, 1200, and 2400 mV for the communication distances of 0, 1, 40, and 80 m and showed a correlation between the increase of the communication noise with the increase of the communication distance. However, the optical communication code-transmitter did not show any sign of communication noise at these four different distances. Therefore, the newly developed optical communication system is an ideal system to avoid false alarms in automatic fire detection system.